Improvement in reheating-furnaces



` H. MODONALD.

Re-heating-Furnaoe.

No. 203,634. v Patented May14, 1878.

N.PETERS. PHOTO-LITHOGRAPHER, WASHINGTON. D` C.

if NITED STATES PATENT OEEIoE.

HUGH MCDONALDV, or ALLEGEENY, PENNSYLVANIA.

IMPROVEMENT IN REHEATING-FURNACES.

Specification forming part of Letters Patent No. 203,634, dated May 14,1878 application filed A April 6, 1878.

To all lwhom it may concern:

Beit known that I, HUGH McDoNALD, of

`Allegheny city, county of Allegheny, State of Pennsylvania, haveinvented or discovered Va new and useful Improvement in Reheating-Furnace; and I'do hereby declare the followingto b e a full, clear,concise, and exact deseription thereof, reference being had to theaccompanying drawing, making a part of this.

specification, in whichlike letters indicating I `like parts- Figure lis an exterior View in perspective, with reverberatory arch or cap,partly in section, of my improved furnace, and illustrative. e of themanner of its use.

sectional view of the4 same. Fig 3 is a like operated on.

My improved furnace is particularly designed 'i for the heating oftheflue-holes of boiler-heads, tube-sheets, Sto., preparatory to thenozzling of the same1 or to the bending of a flange around such holes,Heretofore such work has commonly been done by the use of an orv dinaryblacksmiths re on an open or` plain forge-hearth; but with such a fire,where the part to be heated has to be kept covered by i `or in contactwith the fuel, it has been found ;adifficult to heat the metal uniformlyat` all points around the hole, and the undue heating or overheating ofone part is apt to.so injure, v

the plate as to spoil it for practical use.

The furnace B and flue B. are built of any suitable material, preferablytire-brick, in any4 of the ways known to the art. The furnace has anordinary lire-chamber over an ordinary grating, b but, as anysuitablefuel may be used, the construction of the parts for secur- -ingcombustion may be varied at pleasure,

according to the fuel employed. If a blast is.

used, it may be introduced through any suitable pipe, p. Above thecombustionchamber is the flue B', which may, however, be simply anupward prolongation of the combustionohamber to a sufficient heightabove the ire below, such that no solid fuel shall come in Contact withthe plate a or flue-hole s, which is to be heated.

Fig. 2 is a vertical- The amount of plate which it is necessary to heatwill vary with the size of the flue-hole and the depth of ange to beturned thereon, and an economical use of fuel and expenditure of heatrequire that little or no more of the plate should be heated than isnecessary as a preparatory step to bending; and while it is obvious thatthe iue B may at its upper end be contracted to or made of such size asto heat the proper area of plate where the holes vary but little, if atall, in size, I have found it better to provide removable andinterchangeable throat pieces or rings, which may be placed on top ofthe flue, so as thereby to contract or enlarge at pleasure the size ofthe opening or throat. While not limiting myself to any exactproportions, I deem it best to provide, in this way, a throat or ilueopening the diameter of which will be, say, from two tosix inches (moreor less) greater than the outside diameter of the iiange to be formed 5but these dimensions are not material, `provided only the furnace havethe capacity of givinga good bending heat to the plate through so muchandsuch part of it as is to be subject to the nozzling eifect.

Two such throat-pieces are shown at `R- R. They are made preferably offire-brick banded together. They are made, as shown inthe drawing,sufficiently large to restI upon the top ofthe ilue B; but the openingsthrough them are reduced in diameter, or area, so that `at theupperVside or end such opening has an ,area corresponding closely orapproximately to the area of the plate which it is desired to heat, andthe amormt of such reduction varies in the different throat-pieces. Thusthe throatpiece R has` anopening, c, which adapts it for use in heatingthe metal of the plate a to the desired radial extent around theflue-hole s, preparatory to the nozzling of the same, as shown at d,Fig. 4, while the throat-piece R has an opening, c', which adapts it forlike use as regards a smaller iue-hole, s. In this way I make provisionfor the heating on one side of the desired area or depth of plateimmediately around due-holes of diiferent sizes.

In order to secure the like action of theheat on the upper side of theplate, and to about the same depth or over the same area of surface, Iemploy a reverberatory arch or cap, D

' of the throat-pieces.

Ior D', the different caps differing as to sizes in accordance with thedescribed differences These caps are also made of fire-brick bandedtogether, or of other suitable material, and in any suitable way. Theyare made somewhat ofthe form of the cap or cover of a pepper-box, leachwith a chamber, n, on the Aunder side, preferably dome-shaped, orapproximately so, and the area of such chamber in horizontal section issuch that the desired area of plate shall on its upper face be exposedto the action of the iame and heat, which, passing up through theflue-hole in the plate, is reverberated or deflected downward onto theexposed area of the plate, or is so coniined as to act thereon; but tokeep up the flow of iiame and heat, escape-holes, e, in any desirednumber or order of arrangement, are made in the cap.

In operation the proper throat-piece is put onto the top of the iiue B',the plate is placed thereon, with the flue-hole of the plate over aboutthe center of the flue, and the cap of the proper size is placed on theplate over the iiue-hole, substantially as shown in the drawings. Whenthe flue-hole is near the edge of the plate the opposite edge may besupported by a post, I), or in other convenient way. lAfter the properbending heat has been secured in the plate immediately around thefluehole, the nozzling is done in the usual or any known or desired way.

It is comparatively immaterial at what point or place in o r part of thefurnace the heat is applied to the plate, provided only that it be awayfrom the fuel. Hence the plates,instead i of being placed 0n top of theiiue B', may be placed and supported in any convenient way opposite alateral opening, g or g', in the side of the flue, the top, in suchcase, being closed.

In such mode of workin g or using the invention the throat-piece may beused or not, as before; but the best results require the use ofreverberatory caps or arches outside the plates, in order to secure theproper heating of the exterior. When g or g' is used, the top of theflue B' should be closed, and vice versa, the

important feature in this respect being that the direct line for passageof heat andiiame should be through the opening or throat thus utilizedfor heating purposes.

This apparatus I have found much more convenient for the purpose thanany other now known to me, while it provides for heating uniformly andto the desired degree so much and only so much of the plate as needs tobe heated,

lthus involving convenience and rapidity of manipulation, economy of"fuel, and freedom from the loss which attends the use of fuel over andon the parts to be heated.

In so far as relates to the use of an opentopped or Vopen sided ilue, Ido not include herein any flue the openin g or discharge-throat of whichis not easily accessible to the workman in puttingthe plate or otherarticle to be heated thereon or applyin g it thereto 5 and herein liesthe distinction between the iiue which I employ and an ordinary chimney,and for this purpose Idesiguate my flue as a low flue.77 Also, while I'prefer to make the caps removable, or at least adjustable forconvenience in manipulating the plates, they may also be fixed inposition, and a horizontal slit be leftfor theinsertion and removal ofthe plates, particularly if the plates are not previously flanged; andbythe term plates,7 as used herein, I mean plates having ue-holes madetherein preliminary to nozzling; but in such case the slit or openingmust extend outside of or beyond the furnace-flue opening, so as to makeprovision for the heating of the plate to only the desired extent aroundthe flue hole cut therein, the rest of the plate being protected asagainst heat by the horizontal faces of the slit above and below.

I claim herein as my inventionl. The combination of acombustion-chamber, a low flue,areverberatory cap or arch, and a spacebetween the top ofthe flue and the cap or arch for the insertion of aplate, whereby, whileA a portion of the plate around the ilue-hole cuttherein shall be exposed to the action of 'the heat above and below, therest of the plate will lie outside of the heatingspaces,'substantiallyas set forth. f

2. The combination vof a combustion-chamber, a low flue, and a removablereverberatory cap or arch, substantially as set forth.

3. Removable and interchangeable throatpieces R R' and caps or arches DD', as appendages to a heating-furnace, substantially as and for thepurposes set forth.

4. The combination of combustion-cham ber, low flue, throat-piece, andcap or arch, substantially as set forth.

, In testimony whereofI have hereunto set. my hand.

HUGH MODONALD.

Witnesses:

J. J. McCoRMIcK, OLAUDIUs L. PARKER.

